A human body is composed of water, muscle, bone and fat, in addition to small amounts of special components. The total of these elements constitutes the body weight. Quantitatively measuring the respective elements is called body composition analysis. The proportion occupied by the components other than fat is called fat free mass. Comparison between fat free mass and fat mass is used in identifying various adult diseases. In medical terms, of the body composition, fat free mass (FFM) is the main component for supporting the human body.
Patients suffering from a gradual loss of skeletal muscle mass (sarcopenia) because of aging and/or disease can be quantitatively assessed and identified. Wasting diseases (cachexia) and many health related conditions also result in a decrease of FFM. Furthermore, based on body composition analysis, the growth of children and the nutritional status of the elderly can be quantified.
The various conventional methods for measuring the body composition include (i) using hydrodensitometry, (ii) measuring the thickness of the sub-cutaneous fat layer by using a caliper or near infrared light, (iii) taking photographic images using methods such as nuclear magnetic resonance (NMR) and dual energy X-ray absorptiometry (DEXA), and (iv) using dilution methods such as heavy water (D20) and bromide solution. Hydrodensitometry is highly accurate, and, therefore, is used as a standard method. However, hydrodensitometry is a troublesome task to carry out, and thus cannot be applied to the elderly or to a patient. Measuring the thickness of the sub-cutaneous fat layer has the disadvantage that the accuracy and repeatability is low. Nuclear magnetic resonance (NMR), dual energy X-ray absorptiometry (DEXA), and the dilution methods are expensive to carry out, and, therefore, cannot be applied to general patients in an economical manner.
Another method for measuring the body composition is bioelectrical impedance analysis (BIA). BIA is safe compared with the other conventional methods, the measuring cost is very low, and the measuring can be done in a fast manner. However, measurements made using conventional BIA techniques do not provide the accuracy or repeatability obtained using, for example, nuclear magnetic resonance (NMR), dual energy X-ray absorptiometry (DEXA), and the dilution methods.
It would be desirable to implement a method and/or architecture for determining body composition through segmental bioelectrical impedance analysis (BIA) that could provide accuracy similar to nuclear magnetic resonance (NMR), dual energy X-ray absorptiometry (DEXA), and the dilution methods.